Zoology and wildlife conservation

Effects of nutrient deficiencies and excesses on reproductive efficiency of livestock

Article Abstract:

The effects of nutrient deficiencies and excesses on animal reproduction is discussed. The mechanisms by which these occur are specific for a particular nutrient, with those for excesses being less elucidated than for deficiencies. The degree of body fatness appears to be a reliable indicator of the animal's well-being. Combined with changes in body weight, this may be used to assess reproductive potential. Provision of appropriate amounts of nutrients is essential to ensure optimal reproduction.

Evaluation of ultrasonic estimates of carcass fat thickness and longissimus muscle area in beef cattle

Article Abstract:

The carcass fat thickness and longissimus muscle area of 646 yearling crossbred feedlot steers and heifers were ultrasonically measured 24 h before slaughter and were compared with 48 hour postmortem measurements to evaluate the accuracy of ultrasonic measurements. The actual differences revealed that ultrasonic measurements of backfat and longissimus area taken prior to slaughter may be accurate predictors of final carcass fat thickness and longissimus area in beef cattle.

Research applications of ultrasonic imaging in reproductive biology

Article Abstract:

Ultrasonography is a noninvasive technique that can be used in examining various morphologic characteristics in live animals. This application is valuable in studies on reproductive physiology of large farm animals. The potential applications of ultrasound imaging goes beyond examination of luteal development, ovulation and pregnancy. Its use in studying dynamic reproductive functions enable researchers to observe previously unknown aspects of reproductive biology.